Submitted to: In Vitro Biology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2005
Publication Date: June 30, 2005
Citation: Rajasekaran, K., Cary, J.W., Cleveland, T.E. 2005. Genetic engineering of cotton (Gossypium hirsutum L.) with antifungal proteins or peptides to confer enhanced resistance to fungal pathogens. In Vitro Biology Meeting, June 2005, Baltimore, MD. 41:31-A. Technical Abstract: Cotton crop is affected by several fungal and bacterial pathogens, and the average annual cotton production loss due to diseases in the United States is about 12 percent. The seedling disease complex, fungal wilt pathogens, and boll rots are the major cotton diseases worldwide. Cottonseed is also colonized by the saprophytic fungus, Aspergillus flavus, that produces aflatoxin. Aflatoxin, one of the deadliest mycotoxins known, is produced by the fungus on other crops, as well such as corn, peanuts, and tree nuts. The presence of aflatoxin in cottonseed endangers the health of livestock consuming cottonseed meal and the health of humans consuming milk products from the affected livestock. To effectively eliminate or reduce aflatoxin levels in cottonseed to meet increasingly stringent regulatory levels, a variety of approaches will be necessary. Genetic engineering of cotton with antifungal proteins or peptides is an effective, viable, and environmentally-safe option. We have transformed cotton with a gene encoding for a bacterial chloroperoxidase (cpo-p) or a synthetic antimicrobial peptide (D4E1) to provide resistance or tolerance to phytopathogens including A. flavus. These antifungal proteins have been shown to inhibit growth and development of pre-germinated conidia of A. flavus, Fusarium, and other phytopathogens, including bacterial pathogens at low concentrations. Similar results were obtained earlier with the transgenic tobacco model system. Crude protein extracts from leaf tissue of transgenic tobacco plants expressing the CPO-P or the synthetic peptide D4E1 significantly reduced in vitro the number of fungal colonies arising from germinated conidia of A. flavus, F. verticillioides, and Verticillium dahliae and showed greater levels of disease resistance in planta to the fungal pathogen, Colletotrichum destructivum, which causes anthracnose. In this presentation, we report on the development of transgenic cotton lines expressing the antifungal proteins with enhanced resistance in vitro and in planta to several fungal pathogens including A. flavus.